Bennett J W, Vinnett C H, Goynes W R
Can J Microbiol. 1980 Jun;26(6):706-13. doi: 10.1139/m80-121.
A scanning electron microscopic examination of the surface ornamentation of haploid, heterokaryotic, and diploid conidiospores of Aspergillus parasiticus is presented. Previous studies on the parasexual cycle in this aflatoxin-producing species have shown that heterozygous diploids may be isolated with ease. However, rational genetic analysis of diploids has been hampered by the nonrandom recovery of auxotrophic markers from heterozygous diploids. In this study, a double transfer method involving only brief exposure to p-fluorophenylalanine (FPA) allowed increased recovery of auxotrophic markers from heterozygous diploids. Extensive sampling of green-spored types from FPA-treated diploids provided an estimate of auxotrophic segregants not visually identifiable. We examined seven heterozygous diploids involving three spore color markers and eight auxotrophic markers. In addition, two mutants blocked in aflatoxin production which accumulated visually detectable aflatoxin precursors were analyzed. One linkage between an auxotrophic marker and a spore color marker was detected; however, no evidence for linkage was found between the blocked aflatoxin mutants and the other markers studied.
本文呈现了对寄生曲霉单倍体、异核体和二倍体分生孢子表面纹饰的扫描电子显微镜检查。此前对这种产黄曲霉毒素物种的准性生殖周期的研究表明，杂合二倍体很容易分离出来。然而，由于从杂合二倍体中非随机回收营养缺陷型标记，对二倍体的合理遗传分析受到了阻碍。在本研究中，一种仅涉及短暂暴露于对氟苯丙氨酸（FPA）的双重转移方法，使得从杂合二倍体中回收营养缺陷型标记的效率提高。对经FPA处理的二倍体的绿色孢子类型进行广泛采样，提供了对无法通过视觉识别的营养缺陷型分离体的估计。我们检查了涉及三个孢子颜色标记和八个营养缺陷型标记的七个杂合二倍体。此外，还分析了两个在黄曲霉毒素产生过程中受阻的突变体，它们积累了可通过视觉检测到的黄曲霉毒素前体。检测到一个营养缺陷型标记和一个孢子颜色标记之间存在一个连锁关系；然而，在所研究的受阻黄曲霉毒素突变体与其他标记之间未发现连锁的证据。
